1. Field of the Invention
The present invention relates to recessed strip lighting fixtures. More particularly, this invention relates to a master-satellite retrofit assembly and a method of retrofitting recessed strip lighting fixtures using the assembly.
2. Description of Prior Art
a. Retrofit Recessed Strip Fixture
Higher efficiency, brighter fluorescent lamps with better color rendering are the results of recent development in fluorescent lighting technology. Particularly, these developments have resulted in the availability of new technology lamps with the performance described above. These developments have been of particular interest to large users of recessed strip lighting fixtures, such as department, grocery and other retail stores.
Strip lighting fixtures are commonly utilized in continuous rows to provide economical uniform lighting of large indoor spaces, such as retail stores. Recessing the fixtures above the plane of the ceiling provides for a ‘cleaner’ look and more visual comfort than ‘open’ strip fixtures. In the past, these fixtures typically utilized T-12 sized old technology lamps in 8 foot lengths. The fixtures themselves typically measured 1 foot by 8 foot and were installed into inverted “T” (NEMA “G”) ceiling systems.
Retail stores desire the ability to more efficiently and effectively illuminate their merchandise and their stores by utilizing the newer technology lamps. However, the newer technology lamps cannot be installed into existing strip fixtures as they require different lamp holders and ballasts.
Replacement of existing fixtures would be very costly, requiring the purchase of completely new fixtures, wiring and construction costs of removing the old fixtures and installing the new fixtures, and, most importantly, the inconvenience and cost of closing down sections of the store as the construction proceeds creating “hard hat areas”.
b. Master-Satellite Retrofit Assembly and Method of Retrofitting Recessed Strip Lighting Fixtures
Thus, various devices and methods have been developed to address cost and convenience issues involved with retrofitting existing fixtures with newer technology lamps, sockets, and ballasts. One such device is partially described herein, and is further described in U.S. patent application Ser. No. 09/865,833, which is incorporated herein by reference. The compact retrofit fixture described is able to utilize the housing of the existing fixture that is already in the ceiling as the housing for the retrofit fixture to reduce purchase, installation and disposal costs associated with the retrofit process. Furthermore, the retrofit fixture described also improves the speed and convenience of the retrofit process.
A key advantage of the retrofit fixture is that it allows installation without disturbing the ceiling or the plenum area above it, thereby eliminating potential asbestos and other issues associated with disturbing the ceiling or plenum. A further advantage is that the retrofit fixture may be pre-wired and pre-lamped at the factory. Thus, all the installer has to do is remove the old technology lamps from the existing fixture, move the power connection from the existing ballast to the retrofit fixture ballast, and insert the retrofit fixture into the housing of the existing fixture.
In a typical retrofit of a facility with rows of recessed strip fixtures, the process would proceed from fixture to fixture and row to row, with each existing fixture being retrofitted with a retrofit fixture having a new technology ballast and new technology lamp holders holding new technology lamps.
Advances in lighting technology have further improved the light output available from fluorescent lamps, as well as reducing the size of the electronics, or ballasts, needed to operate such lamps. Thus, high output lamps are now available that produce roughly twice the light output as standard lamps, enabling fixtures to provide equivalent illumination with only half of the lamps previously needed. This consolidation of lamps makes it is possible for one high output electronic ballast to power the lamps in two retrofit fixtures (and possibly more), saving the additional cost of providing each retrofit fixture with a separate ballast. This is known as a master-satellite or master-slave configuration.
This master-satellite configuration is desirable, but requires wiring to extend between the ballast of the master fixture and the lamp sockets of the satellite fixtures. Since such wiring typically does not exist between the independent existing fixtures described above, it is an additional component that must be added as a part of the retrofit process. The additional wiring must be run either on the ceiling side or the room side of the fixtures, either above or below the T-bar member that separates the fixtures.
Since the existing fixtures act as housings for the retrofit fixtures, running the wiring on the ceiling side of the fixtures would require cutting holes in the ends of the existing fixtures, accessing the plenum area, and running conduit or armored cable between the fixtures. Additionally, the wiring would need to be protected from the sharp edges of the holes with bushings or the like. This procedure is undesirable as it greatly increases the time and effort required to install the master-satellite fixtures, and requires disturbing the ceiling and plenum.
Thus, running the wiring between the fixtures on the room side of the fixtures below the T-bar member is the preferred method, as it continues to allow installation without disturbing the ceiling or the plenum, and also permits the master-satellite fixtures to be pre-wired.
However, safety code requirements dictate that the wiring be enclosed. Since conduit, armored cable, or the like, would generally be unsightly to view from the room side of the fixtures, an aesthetically pleasing and functional cover is needed to allow the wiring to run between the fixtures on the room side of the fixtures below the T-bar member between the fixtures.